As a non-contact operation sensing device for a vehicle mentioned above, one described in International Publication WO 2010/076332 (Reference 1) is known. The sensing device described in Reference 1 senses an in and out operation (kick motion) of a foot under the floor of a vehicle body by a capacitance sensor having a wire loop electrode provided at a lower portion of the vehicle body.
In the sensing device of Reference 1, except for a direction in which the non-contact operation which is a target to be sensed when viewed from the wire loop electrode is performed, a portion around the wire loop electrode is covered with the shield electrode, and the shield electrode is driven at the same potential as the wire loop electrode. In this way, the influence of the parasitic capacitance constantly generated between the metal component of the vehicle body such as a skeletal material and the wire loop electrode on the sensing accuracy is suppressed.
By the way, depending on the vehicle, a hitch for trailer connection is provided under the floor of the vehicle body. In a case where such a metal component such as a hitch is provided in the vicinity of the wire loop electrode, the sensing accuracy of the non-contact operation decreases due to the parasitic capacitance constantly generated between the wire loop electrode and the metal component.
Thus, a need exists for a non-contact operation sensing device for a vehicle and a capacitance sensor, which are not susceptible to the drawback mentioned above.